JP4601680B2 - Painting method - Google Patents

Description

  The present invention relates to a coating method for porous inorganic materials such as concrete and cement mortar.

  Conventionally, as a method for imparting water absorption prevention and improving durability to porous inorganic materials such as concrete and cement mortar used as base materials for buildings and civil engineering structures, permeable water absorption prevention materials are used. The method of painting is widely used.

  The permeable water absorption preventing material penetrates into the porous inorganic material to form a water repellent layer. Therefore, by applying such a permeable water absorption preventive material, the intrusion of water, carbon dioxide, etc. from the outside to the base material is blocked, and the strength reduction due to the neutralization of the base material is prevented. An effect of suppressing corrosion of steel frames or reinforcing bars existing inside can be exhibited. It is also possible to prevent the occurrence of efflorescence on the surface of the base material due to the migration of the calcium component inside the base material.

  As such a permeable water absorption preventing material, a material containing a silane compound as a main component (for example, JP-A-63-256581) is known. However, the surface state of the porous inorganic base material to be coated is not necessarily uniform, and the degree of porosity may be partially different. Even if a conventional permeable water absorption preventing material is applied to such a base material, it is difficult to obtain a uniform finish, and it may be difficult to obtain sufficient physical properties in terms of water repellency and water absorption prevention. There is room for practical improvement.

JP-A 63-256581

  The present invention has been made in view of such problems, and an object of the present invention is to provide a simple method capable of imparting excellent finish, water absorption prevention and the like in coating on porous inorganic materials. It is.

In order to solve such problems, the present inventors have intensively studied and came up with a method of applying a specific surface treatment liquid, and completed the present invention.
That is, the coating method of the present invention has the following characteristics.

1. A coating method for applying a surface treatment liquid to the surface of a porous inorganic material,
As the surface treatment liquid,
The alkoxysilane compound contains 0.1 to 50% by weight of an alkoxysilane compound and 50 to 99.9% by weight of a solvent. The alkoxysilane compound has an alkyl group having 3 to 12 carbon atoms and a degree of condensation of 2 or less. A coating method comprising using a surface treatment liquid containing 90% by weight or more of an alkoxysilane compound, and the solvent containing 90% by weight or more of an aliphatic hydrocarbon.
2. A coating method for applying a surface treatment liquid to the surface of a porous inorganic material,
The alkoxysilane compound contains 0.1 to 50% by weight of an alkoxysilane compound and 50 to 99.9% by weight of a solvent. The alkoxysilane compound has an alkyl group having 3 to 12 carbon atoms and a degree of condensation of 2 or less. It contains 90% by weight or more of an alkoxysilane compound,
The solvent, after applying the first surface treatment liquid containing 90% by weight or more of aliphatic hydrocarbons,
A coating method comprising applying a second surface treatment liquid containing 0.1 to 50% by weight of a tetraalkoxysilane compound.
3. 1. The surface of the porous inorganic material is washed with an aqueous solution containing a fluorine compound, and then a surface treatment solution is applied. Or 2. The painting method described.

  In the present invention, by using a specific surface treatment solution, the finish of the porous inorganic material surface, water absorption prevention, etc. can be improved, and as a result, neutralization, strength reduction, efflorescence generation, etc. can also be prevented. it can.

  Hereinafter, the best mode for carrying out the present invention will be described.

  The present invention is applied to porous inorganic materials constituting buildings, civil engineering structures, and the like. Examples of the base material to be coated include concrete, mortar, plaster, cement mortar, PC panel, ALC panel, extruded cement board, ceramic siding board, calcium silicate, stone, and the like.

  In the present invention, the surface treatment liquid is applied to the surface of the porous inorganic material. The surface treatment liquid in the present invention contains an alkoxysilane compound and a solvent.

  Among these, as the alkoxysilane compound, an alkylalkoxysilane compound having an alkyl group with 3 to 12 carbon atoms and a condensation degree of 2 or less (hereinafter simply referred to as “alkylalkoxysilane compound”) is used as an essential component. This alkylalkoxysilane compound penetrates deeply into the base material to form a water-repellent coating, imparts water absorption prevention to the base material, and contributes greatly to improvement in finish, aesthetics retention, and the like. Furthermore, it effectively works to suppress neutralization, strength reduction, efflorescence generation and the like in the base material.

Such an alkylalkoxysilane compound is a compound in which an alkyl group and an alkoxyl group are bonded to a silicon atom. For example, a compound represented by the following formula (1) and / or a condensate thereof can be used.
R ¹ —Si (OR ² ) ₃ (1)
(In the formula, R ¹ and R ² represent an alkyl group. R ¹ has 3 to 12 carbon atoms.)

  Specifically, examples of the compound represented by the above formula (1) include propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane, and hexyltri. Methoxysilane, hexyltriethoxysilane, heptyltrimethoxysilane, heptyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, nonyltrimethoxysilane, nonyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, undecyl Examples include trimethoxysilane, undecyltriethoxysilane, dodecyltrimethoxysilane, and dodecyltriethoxysilane. As these condensates, those having a condensation degree of 2 or less can be used, and in the present invention, a monomer having a condensation degree of 1 is particularly suitable.

  As the alkylalkoxysilane compound, those having 3 to 12 (preferably 5 to 8) carbon atoms in the alkyl group are used. The alkyl group may be partially substituted with halogen or the like. If the number of carbon atoms in the alkyl group is within such a range, it is possible to combine both performance of finishing and water absorption prevention. When the number of carbon atoms of the alkyl group is less than 3, the water absorption preventing property is insufficient, and when it exceeds 12, there is a possibility that the finish is adversely affected.

  Examples of the alkoxyl group in the alkylalkoxysilane compound include those having 1 to 8 (preferably 1 to 4, more preferably 1 to 2) carbon atoms, and a methoxy group having 1 carbon atom is particularly preferable. If the number of carbon atoms of the alkoxyl group is such, advantageous effects in performance such as water absorption prevention can be obtained.

  The ratio of the alkylalkoxysilane compound in the alkoxysilane compound is usually 90% by weight or more (preferably 95% by weight or more, more preferably 98% by weight or more). A form in which the alkoxysilane compound is substantially composed only of the alkylalkoxysilane compound is also suitable. Examples of the alkoxysilane compound other than the alkylalkoxysilane compound include compounds whose carbon number of the alkyl group, the degree of condensation, etc. are not specified above. In the present invention, the alkylalkoxysilane compound can be controlled by reducing the ratio of such components. The effect of the silane compound can be sufficiently exhibited. When the ratio of the alkyl alkoxysilane compound in the alkoxysilane compound is too low, it is difficult to obtain sufficient performance in terms of finish.

  The content ratio of the alkoxysilane compound in the surface treatment liquid is usually 0.1 to 50% by weight, preferably 1 to 30% by weight, and more preferably 2 to 20% by weight. When this content ratio is too low, the water absorption prevention property tends to be insufficient, and conversely, when it is too high, there is a possibility of adversely affecting the finish.

  In the surface treatment liquid of the present invention, a solvent containing 90% by weight or more of aliphatic hydrocarbon is used as a solvent for dissolving the alkylalkoxysilane compound. In the present invention, excellent finish can be obtained by using the above alkylalkoxysilane compound in combination with such a solvent. Furthermore, in this invention, by using such a solvent, the permeability to a base material can be improved and performance improvement, such as water absorption prevention property, can also be aimed at.

As the aliphatic hydrocarbon, an aliphatic saturated hydrocarbon is preferable, and an aliphatic saturated hydrocarbon having 4 or more (more preferably 5 or more) carbon atoms is particularly preferable. Examples of such aliphatic hydrocarbons include butane (C ₄ H ₁₀ ), pentane (C ₅ H ₁₂ ), hexane (C ₆ H ₁₄ ), heptane (C ₇ H ₁₆ ), and octane (C ₈ H _18). ), Nonane (C ₉ H ₂₀ ), decane (C ₁₀ H ₂₂ ), undecane (C ₁₁ H ₂₄ ), dodecane (C ₁₂ H ₂₆ ), tridecane (C ₁₃ H ₂₈ ), tetradecane (C ₁₄ H ₃₀ ), Directly such as pentadecane (C ₁₅ H ₃₂ ), hexadecane (C ₁₆ H ₃₄ ), heptadecane (C ₁₇ H ₃₆ ), octadecane (C ₁₈ H ₃₈ ), nonadecane (C ₁₉ H ₄₀ ), eicosane (C ₂₀ H ₄₂ ), etc. chain aliphatic saturated hydrocarbon, isopentane _{(C 5} H 12), 2- methyl pentane _{(C 6} H 14), 3- methylpentane _{(C 6 H 14} ), 2,2-dimethyl butane _{(C 6} H 14), 2,3- dimethylbutane _{(C 6} H 14), hexane _{(C 7} H 16 to 2-methyl), to 3-methyl hexane _{(C 7 H 16} ), 3-ethyl pentane _{(C 7} H 16), 2,2- dimethyl pentane _{(C 7} H 16), 2,3- dimethyl pentane _{(C 7} H 16), 2,4- dimethyl pentane _{(C 7 H 16} ), 3,3-dimethylpentane (C ₇ H ₁₆ ), 2,2,3-trimethylbutane (C ₇ H ₁₆ ), 2-methylheptane (C ₈ H ₁₈ ), 3-methylheptane (C ₈ H ₁₈₎ ), 2,2-dimethylhexane (C ₈ H ₁₈ ), 2,3-dimethylhexane (C ₈ H ₁₈ ), 2,5-dimethylhexane (C ₈ H ₁₈ ), 3,4-dimethylhexane ( C ₈ H _18), 2,2, - trimethylpentane _{(C 8} H 18), 2,2,4- trimethylpentane _{(C 8} H 18), 2,3,3- trimethylpentane _{(C 8} H 18), 2,3,4- trimethylpentane (C ₈ H _18), 2-methyl-octane _{(C 9} H 20), include branched aliphatic saturated hydrocarbons such as 2-methylnonane _(C 10 _{H 22).} These aliphatic hydrocarbons may be used alone or in combination of two or more.

  The ratio of the aliphatic hydrocarbon needs to be 90% by weight or more in the total solvent, but is preferably 95% by weight or more, more preferably 98% by weight or more. In the present invention, a solvent composed substantially only of aliphatic hydrocarbons is also suitable. When the ratio of the aliphatic hydrocarbon is too low, the surface treatment liquid tends to be non-uniform on the substrate during the application or drying of the surface treatment liquid, which may adversely affect the finish.

  The content ratio of the solvent in the surface treatment liquid is usually 50 to 99.9% by weight, preferably 70 to 99% by weight, and more preferably 80 to 98% by weight. When the content ratio of the solvent is too low, there is a possibility that the finish quality is adversely affected. On the other hand, when the solvent content is too high, the water absorption preventing property tends to be insufficient.

  The surface treatment liquid can be produced by uniformly mixing the above components by a conventional method. In the surface treatment solution, for example, a colorant, a thickener, a wetting agent, an antifreezing agent, an antiseptic, an antifungal agent, an antibacterial agent, an antibacterial agent, and a dispersion may be used, as long as the effects of the present invention are not significantly impaired. An agent, an antifoaming agent, an ultraviolet absorber, an antioxidant, a catalyst, and the like can also be mixed.

In the present invention, the surface treatment liquid is applied to the surface of the porous inorganic material. A coating instrument is not specifically limited, Well-known coating instruments, such as a brush, spray, and a roller, can be used. The required amount for coating the surface treatment liquid may be set as appropriate in consideration of the type and state of the substrate, but is usually about 30 to 500 g / m ² (preferably 80 to 200 g / m ² ), solid In terms of minutes, it is usually about 1 to 250 g / m ² (preferably ² to 100 g / m ² ).
In the coating of the surface treatment liquid, the required amount is within the above range, and the coating can be performed in a plurality of times. In this case, the coating interval is preferably set to be relatively short, and is usually within 8 hours (preferably within 4 hours, more preferably within 2 hours). The application and drying of the surface treatment liquid may be usually performed at room temperature.

  In the present invention, before the surface treatment liquid is applied, the surface of the porous inorganic material can be subjected to treatment such as washing. Specifically, as the cleaning treatment, a method of washing with water after applying various cleaning agents to the surface of the porous inorganic material can be employed. When washing with water, the treatment may be performed while rubbing the surface of the porous inorganic material with a sponge or the like. After the surface subjected to the cleaning treatment is dried, the surface treatment liquid can be applied. In the present invention, the effect of water absorption prevention and the like can be further enhanced by applying the surface treatment liquid after performing the cleaning treatment.

  Specifically, as the cleaning agent, an aqueous solution containing one or more selected from inorganic acids, organic acids, fluorine compounds and the like as an active ingredient is preferable. Among these, examples of the inorganic acid include hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, phosphoric acid, boric acid, phosphorous acid, sulfamic acid, and hypophosphorous acid. Examples of organic acids include monobasic carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, oleic acid, linoleic acid, oxalic acid, malonic acid, succinic acid, maleic acid, Dibasic carboxylic acids such as fumaric acid, itaconic acid, glutaric acid and adipic acid, lactic acid, citric acid, glycolic acid, malic acid, tartaric acid, gluconic acid, ascorbic acid, erythorbic acid and other oxycarboxylic acids, ethylenediaminetetraacetic acid Aminocarboxylic acids such as diethylenetriaminepentaacetic acid, nitrilotriacetic acid, aspartic acid and glutamic acid, sulfonic acids such as paratoluenesulfonic acid, phosphonic acids such as 1-hydroxyethylidene-1,1-diphosphonic acid and aminotrimethylenephosphonic acid Can be mentioned. Examples of the fluorine compound include hydrofluoric acid, ammonium fluoride, acidic ammonium fluoride, ammonium hydrogen fluoride, ammonium fluorosilicate, tetramethylammonium fluoride, tetraethylammonium fluoride, triethylmethylammonium fluoride, and fluorine. Trimethylhydroxyethylammonium fluoride, tetraethanolammonium fluoride, methyltriethanolammonium fluoride, and the like. These may be used in combination of two or more. In the cleaning agent, other components such as a surfactant can be appropriately mixed.

  As the cleaning agent in the present invention, an aqueous solution containing a fluorine compound is particularly suitable. An aqueous solution containing a fluorine compound and an inorganic acid and / or an organic acid is also suitable. The concentration of the fluorine compound in the cleaning agent is usually 0.001 to 3% by weight (preferably 0.005 to 1% by weight). The concentration of the inorganic acid is usually 0 to 30% by weight (preferably 1 to 20% by weight), and the concentration of the organic acid is usually 0 to 30% by weight (preferably 1 to 20% by weight). If the concentration of each component is within such a range, it is excellent in terms of decontamination and also in terms of improving water absorption prevention.

  In the present invention, the surface containing 0.1 to 50% by weight of a tetraalkoxysilane compound as the second surface treatment liquid after coating the above-mentioned surface treatment liquid (hereinafter also referred to as “first surface treatment liquid” for convenience). Treatment liquid can be applied. The effect of the present invention can be further enhanced by coating the surface treatment liquid.

Among the components constituting the second surface treatment liquid, the tetraalkoxysilane compound includes a tetraalkoxysilane represented by the following formula (2) and / or a condensate thereof, or a part of the alkyl group thereof as a polyoxyalkylene group. What modified | denatured by etc. can be used.
Si (OR ³ ) ₄ (2)
(In the formula, R ³ represents an alkyl group.)

  Examples of such tetraalkoxysilanes include tetramethoxysilane, tetraethoxysilane, tetra n-propoxysilane, tetraisopropoxysilane, tetra n-butoxysilane, tetraisobutoxysilane, tetra sec-butoxysilane, tetra-t- Examples thereof include butoxysilane, and those having a mixture of alkyl groups having different carbon numbers can also be used. As these condensates, those having an average degree of condensation of about 1 to 20 (preferably 2 to 10) can be used.

  As the alkoxyl group in the tetraalkoxysilane compound, those having 1 to 8 carbon atoms (preferably 1 to 4, more preferably 1 to 2) are suitable. The content ratio of the tetraalkoxysilane compound in the second surface treatment liquid is usually 0.1 to 50% by weight, preferably 0.5 to 20% by weight, and more preferably 1 to 10% by weight. By using such a tetraalkoxysilane, an excellent effect can be stably obtained.

  The second surface treatment liquid is a solution in which the above tetraalkoxysilane compound is dissolved or dispersed in a medium, and may be dispersed by an emulsifier or the like. Examples of the medium in the surface treatment liquid include a strong solvent system mainly containing an aromatic hydrocarbon solvent, a weak solvent system mainly containing an aliphatic hydrocarbon solvent, and an aqueous system mainly containing water. Various forms can be used. The content ratio of the medium in the second surface treatment liquid is usually 50 to 99.9% by weight, preferably 80 to 99.5% by weight, and more preferably 90 to 99% by weight.

  As a medium in the second surface treatment liquid, a solvent containing 90 wt% or more (preferably 95 wt% or more, more preferably 98 wt% or more) of an aliphatic hydrocarbon is suitable. A solvent composed substantially only of aliphatic hydrocarbons is also suitable. As the aliphatic hydrocarbon, an aliphatic saturated hydrocarbon is preferable, and an aliphatic saturated hydrocarbon having 4 or more (more preferably 5 or more) carbon atoms is particularly preferable. As such an aliphatic hydrocarbon, the thing similar to what was illustrated with the 1st surface treatment liquid can be used. By using such aliphatic hydrocarbons, a stable effect in finish and the like can be obtained.

The second surface treatment liquid may contain an alkoxysilane compound other than the tetraalkoxysilane compound. However, it is desirable to prepare such that at least 30% by weight or more of all alkoxysilane compounds in the second surface treatment liquid are the tetraalkoxysilane compounds.
In addition, the second surface treatment liquid is, for example, a resin component, a colorant, a thickening agent, a wetting agent, an antifreezing agent, an antiseptic, an antifungal agent, and an algae preventing agent within a range that does not significantly impair the effects of the present invention. , An antibacterial agent, a dispersant, an antifoaming agent, an ultraviolet absorber, an antioxidant, a catalyst, and the like may be included.
A 2nd surface treatment liquid can be manufactured by mixing these components uniformly by a conventional method. In the second surface treatment liquid, it is desirable that the resin component is not mixed so much, and the content ratio is lower than that of the tetraalkoxysilane compound in order to sufficiently exert the action of the tetraalkoxysilane compound. The content ratio of the resin component is usually less than 20% by weight (preferably 10% by weight or less), and a form not including the resin component is also suitable. Further, it is not necessary to mix a photocatalyst or the like with the second surface treatment liquid.

The coating of the second surface treatment liquid may be usually performed for 1 hour to 10 days, preferably 3 hours to 7 days after the application of the first surface treatment liquid. A coating instrument is not specifically limited, Well-known coating instruments, such as a brush, spray, and a roller, can be used. The required amount for coating the second surface treatment liquid may be appropriately set in consideration of the type and state of the base material, but is usually 10 to 300 g / m ² (preferably 30 to 150 g / m ² ). About 0.1 to 150 g / m ² (preferably 0.3 to 75 g / m ² ) in terms of solid content. The application and drying of the second surface treatment liquid may be usually performed at room temperature.

  Examples are given below to clarify the features of the present invention.

(Manufacture of surface treatment liquid)
The following raw materials were mixed at a weight ratio shown in Table 1 by a conventional method to produce surface treatment liquids 1 to 9.
・ Alkoxysilane compound 1; hexyltrimethoxysilane (condensation degree 1)
・ Alkoxysilane compound 2; hexyltriethoxysilane (condensation degree 1)
・ Alkoxysilane compound 3; butyltrimethoxysilane (condensation degree 1)
・ Alkoxysilane compound 4; hexyltrimethoxysilane (condensation degree 3)
・ Alkoxysilane compound 5; hexyltrimethoxysilane (condensation degree 6)
・ Solvent 1: Mixture of saturated hydrocarbons with 9 or more carbon atoms ・ Solvent 2: Aliphatic hydrocarbon solvent (containing 30% by weight of aromatic hydrocarbons)
・ Solvent 3; aromatic hydrocarbon solvent (aromatic hydrocarbon 100% by weight)

[Test 1]
(Test specimen production)
Using the surface treatment liquids 1 to 9 obtained by the above method, test specimens were respectively produced by the following methods.

After spray coating the entire surface of the test substrate made of cement mortar with a required amount of 100 g / m ^2, it is dried for 1 hour in the standard state (temperature 23 ° C., relative humidity 50%), and then the same surface The treatment liquid was spray coated again at the required amount of 100 g / m ² . Then, it was dried for 24 hours in a standard state.

(Test method and test results)
First, the following test was performed on the test plate obtained by the above method.
-Finishing property The surface of the test plate after coating was observed to confirm whether there was any abnormality in the drying process or whether there was any abnormality in the appearance after drying.
-Permeability The test plate was divided into two, and the color change when water was sprayed on the cross section was observed, and the average value of the thickness of the portion where the color did not change with water was calculated.

  As a result of the above test, the surface treatment liquids 1 to 5 were good in the finish test. In the surface treatment liquids 6 to 9, some unevenness was observed in the appearance after drying. In the permeability test, the surface treatment liquids 1 to 5, 8 and 9 were about 3 mm, and the surface treatment liquids 6 to 7 were about 2.5 mm.

  For the surface treatment liquids 1 to 5 in which good results were obtained in any of the above tests, the test plate was fixed vertically, and water was continuously sprinkled on the test plate using a hose for 1 minute. The water repellency and color change were observed. As a result, in the surface treatment liquids 1 to 3, the water repellency was high and no color change was observed. On the other hand, in the surface treatment liquids 4-5, the water repellency was low compared with the surface treatment liquids 1-3, and the wet color was recognized after the test.

[Test 2]
In Test 2, the test was performed using the following various cleaning agents.
-Detergent 1; 0.6 wt% ammonium fluoride aqueous solution-Detergent 2; Mixed aqueous solution of 0.5 wt% ammonium fluoride, 3 wt% phosphoric acid, 10 wt% lactic acid-Detergent 3; 3 wt% phosphoric acid %, Lactic acid 10% by weight mixed aqueous solution

(Test specimen production)
A cleaning agent was applied to the entire surface of the test base material (cement mortar) that was soiled by exposure to the outdoors, and allowed to stand for about 30 seconds, and then washed with water while rubbing with a sponge. After drying for 24 hours under standard conditions, after spray coating the entire surface of the surface treatment liquid 1 in the required amount 100 g / m ^2, dried for 1 hour at standard conditions, then the same surface treatment liquid 1 in the required amount 100 g / m ² The entire surface was sprayed again. Then, it was dried for 24 hours in a standard state.

(Test method and test results)
About the test plate obtained by the said method, the finish and the permeability test were done by the method similar to the test 1. FIG. As a result, the finish was good when any cleaning agent was used. The values of the permeability test were all about 3 mm.

  Moreover, when the test plate was fixed vertically, water was continuously sprayed on the test plate using a hose for 1 minute, and when the water repellency and color change of the test plate surface were observed, the cleaning agents 1 and 2 were used. In the product, water repellency was high and no color change was observed. On the other hand, in the thing using the cleaning agent 3, the water repellency was a little low compared with the thing using the cleaning agents 1-2.

[Test 3]
(Test specimen production)
The cleaning agent 1 was applied to the entire surface of the test substrate made of the same cement mortar as in the test 1, and after being left for about 30 seconds, it was washed with water while rubbing with a sponge. After drying for 24 hours at standard conditions, the surface treatment liquid 4 in the required amount 100 g / m ² was spray-coated on the entire surface, dried for 1 hour at standard conditions, then the same surface treatment liquid 4 in the required amount 100 g / m ² The entire surface was sprayed again. Then, it was dried for 24 hours in a standard state.
On the other hand, for comparison, a test body coated with the surface treatment liquid 4 was prepared without the cleaning treatment with the cleaning agent 1.

(Test method and test results)
About the test plate obtained by the said method, the finish and the permeability test were done by the method similar to the test 1. FIG. As a result, all the specimens had good finishing properties, and the value of the permeability test was about 3 mm.

  Next, the test plate was fixed vertically, water was continuously sprayed on the test plate using a hose for 1 minute, and the water repellency and color change on the surface of the test plate were observed. The water repellency was improved and the wet color level was slight compared to that without the washing treatment.

[Test 4]
In Test Example 4, the test was performed using the following treatment liquid as the second surface treatment liquid.
-Surface treatment liquid 10: Mixture of tetramethoxysilane condensate (average condensation degree 4) and solvent 1, weight ratio 2:98
-Surface treatment liquid 11: mixture of tetramethoxysilane condensate (average condensation degree 8) and solvent 1, weight ratio 2:98
-Surface treatment liquid 12; mixture of tetramethoxysilane condensate (average condensation degree 4) and solvent 1, weight ratio 4:96

(Test specimen production)
A test substrate made of the same cement mortar as in Test 1 was spray-coated on the entire surface with a required amount of 120 g / m ² as the first surface treatment liquid, and then dried in a standard state for 3 hours. . Next, the entire surface of the second surface treatment liquid was spray-coated at a required amount of 50 g / m ² and dried in a standard state for 24 hours.

(Test method and test results)
About the test plate obtained by the said method, the finish and the permeability test were done by the method similar to the test 1. FIG. As a result, all the test bodies using the surface treatment liquids 10 to 12 as the second surface treatment liquid had good finish, and the value of the permeability test was about 3 mm.

  Next, the test plate was fixed vertically, water was continuously sprayed on the test plate using a hose for 1 minute, and the water repellency and color change of the test plate surface were observed. As a result, water repellency was high and no color change was observed.

[Test 5]
(Test specimen production)
A test substrate made of the same cement mortar as in Test 1 was spray-coated with a surface treatment solution 4 as a first surface treatment solution at a required amount of 120 g / m ² and then dried in a standard state for 3 hours. . Next, the entire surface of the surface treatment liquid 10 as a second surface treatment liquid was spray-coated at a required amount of 50 g / m ² and dried in a standard state for 24 hours.
On the other hand, the surface treatment liquid 4 was spray-coated on the entire surface at a required amount of 120 g / m ² on the test substrate made of the same cement mortar as in Test 1, and then dried in a standard state for 3 hours, and then the surface treatment liquid 4 was spray-coated on the entire surface again at a required amount of 50 g / m ² and dried in a standard state for 24 hours to prepare a test body.

(Test method and test results)
About the test plate obtained by the said method, the finish and the permeability test were done by the method similar to the test 1. FIG. As a result, all the specimens had good finishing properties, and the value of the permeability test was about 3 mm.

Next, the test plate was fixed vertically, water was continuously sprayed on the test plate using a hose for 1 minute, and the water repellency and color change of the test plate surface were observed. As a result, water repellency is improved in the case where the surface treatment liquid 4 is used as the first surface treatment liquid and the surface treatment liquid 10 is used as the second surface treatment liquid compared to the case where only the surface treatment liquid 4 is used. The degree of wet color was also slight.

Claims (1)

A coating method for applying a surface treatment liquid to the surface of a porous inorganic material,
As the surface treatment liquid,
The alkoxysilane compound contains 0.1 to 50% by weight of an alkoxysilane compound and 50 to 99.9% by weight of a solvent. The alkoxysilane compound has an alkyl group having 3 to 12 carbon atoms and a degree of condensation of 2 or less. A coating method comprising using a surface treatment liquid containing 90% by weight or more of an alkoxysilane compound, and the solvent containing 90% by weight or more of an aliphatic hydrocarbon.